The mineral stishovite helps us determine the size of past meteorite impacts, because it forms only at the high pressure and temperature possible only in the most energetic meteorite strikes. Silica also needs to be present for it to form, which helps constrain what type of rock the meteorite hit. This rare mineral was first discovered in Arizona's Meteor Crater in 1962. Now, Kaneko et al. have found a small grain of stishovite in a Moon rock collected by the Apollo 15 mission. A more complete search for stishovite in lunar samples will provide a new path for reconstructing the impact history of the Moon.